激光激励下石英音叉的振动分析与测量

Vibration Analysis and Measurement for Quartz Tuning Fork under Laser Irradiation

针对民航客机微量爆炸物的检测这一难题,对采用石英音叉的光声信号探测原理进行了分析,对光声光谱遥测的光路进行了简化,减少了激光能量的损失,然后建立了实验系统,对石英音叉在激光直接激励时的幅频特性进行了测试,探讨了激光光照位置对于石英音叉振幅的影响。结果表明,当激光光斑在石英音叉叉臂根部偏上约0.2mm处时,石英音叉振幅达到最大值,激光光斑继续向上移动,石英音叉振幅减小,验证了石英音叉振幅与激光功率成正比这一论点。该研究为后续开展远距离光声光谱遥测奠定了基础。

The trace explosive detection in airline security is still difficult. The principle of detecting the photo-acoustic signals produced by quartz tuning fork is analyzed, then the optical path is simplified with the propose to reduce the energy loss of laser. After the analysis of the amplitude of the quartz tuning fork and the signals produced by the quartz tuning fork, an experimental system is established and the amplitude-frequency characteristic curve of the quartz tuning fork irradiated by laser is acquired. In addition, the influence of the location of laser spot on the amplitude of the quartz tuning fork is measured. And it shows that the amplitude of the quartz tuning fork reaches the maximum when the laser spot is about 0. 2 mm above the bottom of the prongs of the quartz tuning fork, laser spot moves up along the prongs, the amplitude decreases gradually, and the fact that the amplitude of the quartz tuning fork is proportional to the laser energy is verified. It is expected to apply to standoff photo-acoustic spectroscopy detec- tion.